First of all, avoid "y" as a name for a function, since it is a keyword.

\&x() evaluates, like \(1, 2, 3) does, to a list of references to the values in the original list: (\1, \2, \3). See perlref.

You can construct an anonymous array and have your second function (I'll call it "yy") return a reference to that:

sub yy { [ x() ] }

(Avoid "&" except when you really need it.)